Python to generate nice looking SVG graph http://pygal.org/
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#!python
# -*- coding: UTF-8 -*-
from operator import itemgetter
from itertools import islice
import pkg_resources
import functools
import cssutils
from lxml import etree
from svg.charts import css # causes the SVG profile to be loaded
try:
import zlib
except ImportError:
zlib = None
def sort_multiple(arrays):
"sort multiple lists (of equal size) using the first list for the sort keys"
tuples = zip(*arrays)
tuples.sort()
return zip(*tuples)
class Graph(object):
"""
Base object for generating SVG Graphs
Synopsis
This class is only used as a superclass of specialized charts. Do not
attempt to use this class directly, unless creating a new chart type.
For examples of how to subclass this class, see the existing specific
subclasses, such as svn.charts.Pie.
* svg.charts.bar
* svg.charts.line
* svg.charts.pie
* svg.charts.plot
* svg.charts.time_series
"""
width= 500
height= 300
show_x_guidelines= False
show_y_guidelines= True
show_data_values= True
min_scale_value= None
show_x_labels= True
stagger_x_labels= False
rotate_x_labels= False
step_x_labels= 1
step_include_first_x_label= True
show_y_labels= True
rotate_y_labels= False
stagger_y_labels= False
step_include_first_y_label= True
step_y_labels= 1
scale_integers= False
show_x_title= False
x_title= 'X Field names'
show_y_title= False
y_title_text_direction= 'bt' # 'bt' for bottom to top; 'tb' for top to bottom
y_title= 'Y Scale'
show_graph_title= False
graph_title= 'Graph Title'
show_graph_subtitle= False
graph_subtitle= 'Graph Subtitle'
key= True
key_position= 'right' # 'bottom' or 'right',
font_size= 12
title_font_size= 16
subtitle_font_size= 14
x_label_font_size= 12
x_title_font_size= 14
y_label_font_size= 12
y_title_font_size= 14
key_font_size= 10
css_inline= False
add_popups= False
top_align = top_font = right_align = right_font = 0
compress = False
stylesheet_names = ['graph.css']
def __init__(self, config = {}):
"""Initialize the graph object with the graph settings."""
if self.__class__ is Graph:
raise NotImplementedError, "Graph is an abstract base class"
self.load_config(config)
self.clear_data()
self.style = {}
def load_config(self, config):
self.__dict__.update(config)
def add_data(self, conf):
"""
Add data to the graph object. May be called several times to add
additional data sets.
>>> data_sales_02 = [12, 45, 21] # doctest: +SKIP
>>> graph.add_data({ # doctest: +SKIP
... 'data': data_sales_02,
... 'title': 'Sales 2002'
... }) # doctest: +SKIP
"""
self.validate_data(conf)
self.process_data(conf)
self.data.append(conf)
def validate_data(self, conf):
try:
assert(isinstance(conf['data'], (tuple, list)))
except TypeError, e:
raise TypeError, "conf should be dictionary with 'data' and other items"
except AssertionError:
if not hasattr(conf['data'], '__iter__'):
raise TypeError, "conf['data'] should be tuple or list or iterable"
def process_data(self, data): pass
def clear_data(self):
"""
This method removes all data from the object so that you can
reuse it to create a new graph but with the same config options.
>>> graph.clear_data() # doctest: +SKIP
"""
self.data = []
def burn(self):
"""
Process the template with the data and
config which has been set and return the resulting SVG.
Raises ValueError when no data set has
been added to the graph object.
"""
if not self.data: raise ValueError("No data available")
if hasattr(self, 'calculations'): self.calculations()
self.start_svg()
self.calculate_graph_dimensions()
self.foreground = etree.Element("g")
self.draw_graph()
self.draw_titles()
self.draw_legend()
self.draw_data()
self.graph.append(self.foreground)
self.render_inline_styles()
return self._burn_compressed()
def _burn_compressed(self):
if self.compress and not zlib:
self.root.addprevious(etree.Comment('Python zlib not available for SVGZ'))
data = etree.tostring(self.root, pretty_print=True, xml_declaration=True, encoding='utf-8')
if self.compress and zlib:
data = zlib.compress(data)
return data
KEY_BOX_SIZE = 12
def calculate_left_margin(self):
"""
Calculates the margin to the left of the plot area, setting
border_left.
"""
bl = 7
# Check for Y labels
if self.rotate_y_labels:
max_y_label_height_px = self.y_label_font_size
else:
label_lengths = map(len, self.get_y_labels())
max_y_label_len = max(label_lengths)
max_y_label_height_px = 0.6 * max_y_label_len * self.y_label_font_size
if self.show_y_labels: bl += max_y_label_height_px
if self.stagger_y_labels: bl += max_y_label_height_px + 10
if self.show_y_title: bl += self.y_title_font_size + 5
self.border_left = bl
def max_y_label_width_px(self):
"""
Calculate the width of the widest Y label. This will be the
character height if the Y labels are rotated.
"""
if self.rotate_y_labels:
return self.font_size
def calculate_right_margin(self):
"""
Calculate the margin in pixels to the right of the plot area,
setting border_right.
"""
br = 7
if self.key and self.key_position == 'right':
max_key_len = max(map(len, self.keys()))
br += max_key_len * self.key_font_size * 0.6
br += self.KEY_BOX_SIZE
br += 10 # Some padding around the box
self.border_right = br
def calculate_top_margin(self):
"""
Calculate the margin in pixels above the plot area, setting
border_top.
"""
self.border_top = 5
if self.show_graph_title: self.border_top += self.title_font_size
self.border_top += 5
if self.show_graph_subtitle: self.border_top += self.subtitle_font_size
def add_popup(self, x, y, label):
"""
Add pop-up information to a point on the graph.
"""
txt_width = len(label) * self.font_size * 0.6 + 10
tx = x + [5,-5][int(x+txt_width > self.width)]
anchor = ['start', 'end'][x+txt_width > self.width]
style = 'fill: #000; text-anchor: %s;' % anchor
id = 'label-%s' % label
t = etree.SubElement(self.foreground, 'text', {
'x': str(tx),
'y': str(y - self.font_size),
'visibility': 'hidden',
'style': style,
'text': label,
'id': id
})
# add the circle element to the foreground
visibility = "document.getElementById(%s).setAttribute('visibility', %%s)" % id
t = etree.SubElement(self.foreground, 'circle', {
'cx': str(x),
'cy': str(y),
'r': str(10),
'style': 'opacity: 0;',
'onmouseover': visibility % 'visible',
'onmouseout': visibility % 'hidden',
})
def calculate_bottom_margin(self):
"""
Calculate the margin in pixels below the plot area, setting
border_bottom.
"""
bb = 7
if self.key and self.key_position == 'bottom':
bb += len(self.data) * (self.font_size + 5)
bb += 10
if self.show_x_labels:
max_x_label_height_px = self.x_label_font_size
if self.rotate_x_labels:
label_lengths = map(len, self.get_x_labels())
max_x_label_len = reduce(max, label_lengths)
max_x_label_height_px *= 0.6 * max_x_label_len
bb += max_x_label_height_px
if self.stagger_x_labels: bb += max_x_label_height_px + 10
if self.show_x_title: bb += self.x_title_font_size + 5
self.border_bottom = bb
def draw_graph(self):
"""
The central logic for drawing the graph.
Sets self.graph (the 'g' element in the SVG root)
"""
transform = 'translate (%s %s)' % (self.border_left, self.border_top)
self.graph = etree.SubElement(self.root, 'g', transform=transform)
etree.SubElement(self.graph, 'rect', {
'x': '0',
'y': '0',
'width': str(self.graph_width),
'height': str(self.graph_height),
'class': 'graphBackground'
})
#Axis
etree.SubElement(self.graph, 'path', {
'd': 'M 0 0 v%s' % self.graph_height,
'class': 'axis',
'id': 'xAxis'
})
etree.SubElement(self.graph, 'path', {
'd': 'M 0 %s h%s' % (self.graph_height, self.graph_width),
'class': 'axis',
'id': 'yAxis'
})
self.draw_x_labels()
self.draw_y_labels()
def x_label_offset(self, width):
"""
Return an offset for drawing the x label. Currently returns 0.
"""
# consider width/2 for centering the labels
return 0
def make_datapoint_text(self, x, y, value, style=None):
"""
Add text for a datapoint
"""
if not self.show_data_values:
# do nothing
return
# first lay down the text in a wide white stroke to
# differentiate it from the background
e = etree.SubElement(self.foreground, 'text', {
'x': str(x),
'y': str(y),
'class': 'dataPointLabel',
'style': '%(style)s stroke: #fff; stroke-width: 2;' % vars(),
})
e.text = str(value)
# then lay down the text in the specified style
e = etree.SubElement(self.foreground, 'text', {
'x': str(x),
'y': str(y),
'class': 'dataPointLabel'})
e.text = str(value)
if style: e.set('style', style)
def draw_x_labels(self):
"Draw the X axis labels"
if self.show_x_labels:
labels = self.get_x_labels()
count = len(labels)
labels = enumerate(iter(labels))
start = int(not self.step_include_first_x_label)
labels = islice(labels, start, None, self.step_x_labels)
map(self.draw_x_label, labels)
self.draw_x_guidelines(self.field_width(), count)
def draw_x_label(self, label):
label_width = self.field_width()
index, label = label
text = etree.SubElement(self.graph, 'text', {'class': 'xAxisLabels'})
text.text = label
x = index * label_width + self.x_label_offset(label_width)
y = self.graph_height + self.x_label_font_size + 3
t = 0 - (self.font_size / 2)
if self.stagger_x_labels and (index % 2):
stagger = self.x_label_font_size + 5
y += stagger
graph_height = self.graph_height
path = etree.SubElement(self.graph, 'path', {
'd': 'M%(x)f %(graph_height)f v%(stagger)d' % vars(),
'class': 'staggerGuideLine'
})
text.set('x', str(x))
text.set('y', str(y))
if self.rotate_x_labels:
transform = 'rotate(90 %d %d) translate(0 -%d)' % \
(x, y-self.x_label_font_size, self.x_label_font_size/4)
text.set('transform', transform)
text.set('style', 'text-anchor: start')
else:
text.set('style', 'text-anchor: middle')
def y_label_offset(self, height):
"""
Return an offset for drawing the y label. Currently returns 0.
"""
# Consider height/2 to center within the field.
return 0
def get_field_width(self):
return float(self.graph_width - self.font_size*2*self.right_font) / \
(len(self.get_x_labels()) - self.right_align)
field_width = get_field_width
def get_field_height(self):
return float(self.graph_height - self.font_size*2*self.top_font) / \
(len(self.get_y_labels()) - self.top_align)
field_height = get_field_height
def draw_y_labels(self):
"Draw the Y axis labels"
if not self.show_y_labels:
# do nothing
return
labels = self.get_y_labels()
count = len(labels)
labels = enumerate(iter(labels))
start = int(not self.step_include_first_y_label)
labels = islice(labels, start, None, self.step_y_labels)
map(self.draw_y_label, labels)
self.draw_y_guidelines(self.field_height(), count)
def get_y_offset(self):
result = self.graph_height + self.y_label_offset(self.field_height())
if not self.rotate_y_labels: result += self.font_size/1.2
return result
y_offset = property(get_y_offset)
def draw_y_label(self, label):
label_height = self.field_height()
index, label = label
text = etree.SubElement(self.graph, 'text', {'class': 'yAxisLabels'})
text.text = label
y = self.y_offset - (label_height * index)
x = {True: 0, False:-3}[self.rotate_y_labels]
if self.stagger_y_labels and (index % 2):
stagger = self.y_label_font_size + 5
x -= stagger
path = etree.SubElement(self.graph, 'path', {
'd': 'M%(x)f %(y)f h%(stagger)d' % vars(),
'class': 'staggerGuideLine'
})
text.set('x', str(x))
text.set('y', str(y))
if self.rotate_y_labels:
transform = 'translate(-%d 0) rotate (90 %d %d)' % \
(self.font_size, x, y)
text.set('transform', transform)
text.set('style', 'text-anchor: middle')
else:
text.set('y', str(y - self.y_label_font_size/2))
text.set('style', 'text-anchor: end')
def draw_x_guidelines(self, label_height, count):
"Draw the X-axis guidelines"
if not self.show_x_guidelines: return
# skip the first one
for count in range(1,count):
start = label_height*count
stop = self.graph_height
path = etree.SubElement(self.graph, 'path', {
'd': 'M %(start)s 0 v%(stop)s' % vars(),
'class': 'guideLines'})
def draw_y_guidelines(self, label_height, count):
"Draw the Y-axis guidelines"
if not self.show_y_guidelines: return
for count in range(1, count):
start = self.graph_height - label_height*count
stop = self.graph_width
path = etree.SubElement(self.graph, 'path', {
'd': 'M 0 %(start)s h%(stop)s' % vars(),
'class': 'guideLines'})
def draw_titles(self):
"Draws the graph title and subtitle"
if self.show_graph_title: self.draw_graph_title()
if self.show_graph_subtitle: self.draw_graph_subtitle()
if self.show_x_title: self.draw_x_title()
if self.show_y_title: self.draw_y_title()
def draw_graph_title(self):
text = etree.SubElement(self.root, 'text', {
'x': str(self.width / 2),
'y': str(self.title_font_size),
'class': 'mainTitle'})
text.text = self.graph_title
def draw_graph_subtitle(self):
y_subtitle_options = [subtitle_font_size, title_font_size+10]
y_subtitle = y_subtitle_options[self.show_graph_title]
text = etree.SubElement(self.root, 'text', {
'x': str(self.width/2),
'y': str(y_subtitle),
'class': 'subTitle',
})
text.text = self.graph_title
def draw_x_title(self):
y = self.graph_height + self.border_top + self.x_title_font_size
if self.show_x_labels:
y_size = self.x_label_font_size+5
if self.stagger_x_labels: y_size*=2
y += y_size
x = self.width / 2
text = etree.SubElement(self.root, 'text', {
'x': str(x),
'y': str(y),
'class': 'xAxisTitle',
})
text.text = self.x_title
def draw_y_title(self):
x = self.y_title_font_size
if self.y_title_text_direction=='bt':
x += 3
rotate = -90
else:
x -= 3
rotate = 90
y = self.height / 2
text = etree.SubElement(self.root, 'text', {
'x': str(x),
'y': str(y),
'class': 'yAxisTitle',
})
text.text = self.y_title
text.set('transform', 'rotate(%(rotate)d, %(x)s, %(y)s)' % vars())
def keys(self):
return map(itemgetter('title'), self.data)
def draw_legend(self):
if not self.key:
# do nothing
return
group = etree.SubElement(self.root, 'g')
for key_count, key_name in enumerate(self.keys()):
y_offset = (self.KEY_BOX_SIZE * key_count) + (key_count * 5)
etree.SubElement(group, 'rect', {
'x': '0',
'y': str(y_offset),
'width': str(self.KEY_BOX_SIZE),
'height': str(self.KEY_BOX_SIZE),
'class': 'key%s' % (key_count + 1),
})
text = etree.SubElement(group, 'text', {
'x': str(self.KEY_BOX_SIZE + 5),
'y': str(y_offset + self.KEY_BOX_SIZE),
'class': 'keyText'})
text.text = key_name
if self.key_position == 'right':
x_offset = self.graph_width + self.border_left + 10
y_offset = self.border_top + 20
if self.key_position == 'bottom':
x_offset, y_offset = self.calculate_offsets_bottom()
group.set('transform', 'translate(%(x_offset)d %(y_offset)d)' % vars())
def calculate_offsets_bottom(self):
x_offset = self.border_left + 20
y_offset = self.border_top + self.graph_height + 5
if self.show_x_labels:
max_x_label_height_px = x_label_font_size
if self.rotate_x_labels:
longest_label_length = max(map(len, self.get_x_labels()))
# note: I think 0.6 is the ratio of width to height of characters
max_x_label_height_px *= longest_label_length * 0.6
y_offset += max_x_label_height_px
if self.stagger_x_labels:
y_offset += max_x_label_height_px + 5
if self.show_x_title:
y_offset += x_title_font_size + 5
return x_offset, y_offset
def render_inline_styles(self):
"Hard-code the styles into the SVG XML if style sheets are not used."
if not self.css_inline:
# do nothing
return
styles = self.parse_css()
for node in xpath.Evaluate('//*[@class]', self.root):
cl = node.getAttribute('class')
style = styles[cl]
if node.hasAttribute('style'):
style += node.getAttribute('style')
node.setAttribute('style', style)
def parse_css(self):
"""
Take a .css file (classes only please) and parse it into a dictionary
of class/style pairs.
"""
# todo: save the prefs for use later
#orig_prefs = cssutils.ser.prefs
cssutils.ser.prefs.useMinified()
get_pair = lambda r: (r.selectorText, r.style.cssText)
result = dict(map(get_pair, self.get_stylesheet()))
return result
def add_defs(self, defs):
"""
Override and place code to add defs here. TODO: what are defs?
"""
def start_svg(self):
"Base SVG Document Creation"
SVG_NAMESPACE = 'http://www.w3.org/2000/svg'
SVG = '{%s}' % SVG_NAMESPACE
NSMAP = {
None: SVG_NAMESPACE,
'xlink': 'http://www.w3.org/1999/xlink',
'a3': 'http://ns.adobe.com/AdobeSVGViewerExtensions/3.0/',
}
self.root = etree.Element(SVG+"svg", attrib={
'width': str(self.width),
'height': str(self.height),
'viewBox': '0 0 %s %s' % (self.width, self.height),
'{http://ns.adobe.com/AdobeSVGViewerExtensions/3.0/}scriptImplementation': 'Adobe',
}, nsmap=NSMAP)
if hasattr(self, 'style_sheet_href'):
pi = etree.ProcessingInstruction(
'xml-stylesheet',
'href="%s" type="text/css"' % self.style_sheet_href
)
self.root.addprevious(pi)
comment_strings = (
' Created with SVG.Graph ',
' SVG.Graph by Jason R. Coombs ',
' Based on SVG::Graph by Sean E. Russel ',
' Based on Perl SVG:TT:Graph by Leo Lapworth & Stephan Morgan ',
' '+'/'*66,
)
map(self.root.append, map(etree.Comment, comment_strings))
defs = etree.SubElement(self.root, 'defs')
self.add_defs(defs)
if not hasattr(self, 'style_sheet_href') and not self.css_inline:
self.root.append(etree.Comment(' include default stylesheet if none specified '))
style = etree.SubElement(defs, 'style', type='text/css')
# TODO: the text was previously escaped in a CDATA declaration... how
# to do that with etree?
style.text = self.get_stylesheet().cssText
self.root.append(etree.Comment('SVG Background'))
rect = etree.SubElement(self.root, 'rect', {
'width': str(self.width),
'height': str(self.height),
'x': '0',
'y': '0',
'class': 'svgBackground'})
def calculate_graph_dimensions(self):
self.calculate_left_margin()
self.calculate_right_margin()
self.calculate_bottom_margin()
self.calculate_top_margin()
self.graph_width = self.width - self.border_left - self.border_right
self.graph_height = self.height - self.border_top - self.border_bottom
@staticmethod
def load_resource_stylesheet(name, subs=dict()):
css_stream = pkg_resources.resource_stream('svg.charts', name)
css_string = css_stream.read()
css_string = css_string % subs
sheet = cssutils.parseString(css_string)
return sheet
def get_stylesheet_resources(self):
"Get the stylesheets for this instance"
# allow css to include class variables
class_vars = class_dict(self)
loader = functools.partial(self.load_resource_stylesheet,
subs=class_vars)
sheets = map(loader, self.stylesheet_names)
return sheets
def get_stylesheet(self):
cssutils.log.setLevel(30) # disable INFO log messages
def merge_sheets(s1, s2):
map(s1.add, s2)
return s1
return reduce(merge_sheets, self.get_stylesheet_resources())
class class_dict(object):
"Emulates a dictionary, but retrieves class attributes"
def __init__(self, obj):
self.__obj__ = obj
def __getitem__(self, item):
return getattr(self.__obj__, item)
def keys(self):
# dir returns a good guess of what attributes might be available
return dir(self.__obj__)